^^ To Start the coop Map:1. Download this map at {LINK REMOVED}http://www.file-upload.net/download-4362790/mp_coop_sandbox.zip.html2.Unzip "mp_coop_sandbox.zip"3. Cut and paste the file ("mp_coop_sandbox.bsp") in the following directory:"your steam directory\steamapps\common\portal 2\portal2\maps\"4.Open Portal 25. Start new cooperative game with your friend;6. Then you need to open in-game console;7. And write this: changelevel mp_coop_sandbox8.HAVE FUN WITH YOUR FRIEND! :D